2008 CRF250R - QS138v3 70H - ANT - Sanyo UR18650-RX 20s20p - Votol EM260

[bananu7]

Hey, I have that throttle too, it's basically this one, right? Can you share the file, I'd love to print and try it out.

Here are the files.

Summary:
* Ref - exact copy of original, but holes are much too small (8x8mm center, 6mm cable)
* V1 - new cam profile, but holes still too small (first one I printed) - I filed it by hand to fit, but took a bit of effort.
* V2 - same cam profile, rotated center hole to pick up cable length (by about 8mm), has enlarged holes (8.2mm center, 6.1mm cable) - and that's still not enough, I'd add another .1mm offset to both.

To change the overall cable length, just rotate the middle mounting hole.

This is how it looks sliced - I've realized i haven't actually shown the cam itself.

 

[amberwolf]

The turn angle is still larger than the Surron throttle, so it should give me good enough modulation at slow speeds.

If you print it as an eccentric cam, with a logarithmic-type shape, you can give yourself fine low-throttle control but accelerated action at higher throttle positions.

EDIT: nevermind, I just reread your post after seeing your cutaway....

 

[harrisonpatm]

Thanks!

 

[harrisonpatm]

3d printing is pretty cool.

 

[bananu7]

While I'm slowly chipping away at the new wiring loom (will get a separate more detailed post), here's a tiny clip from my downhill run.

My perspective on bike weight has really shifted recently. I used to think I would love a 50kg electric motorbike, but I'm getting more and more confident that I'd rather have better suspension than less weight in the vast majority of the circumstances. I've jumped those tiny hops on multiple bikes, including a modern trailbike, and I feel by far the safest on the CRF. It's hard to beat the stability of 80f/110r tyres and 315mm of suspension travel that make it feel like it's nothing - and for a good reason, since it can land from much much higher. One might call it overkill, I call it valuing my life and health and still wanting to get a bit of air action.

 

[bananu7]

It rained today and was slippery as hell, so perfect for some obstacle practice:



I'm working on controlling the blip without a clutch. It's mildly scary, but manageable - I see myself making the same sort of mistakes as on the gas bike.

Also rear shock is definitely too soft. Not sure if I'll go up a spring or harder compression yet, but it's dropping way too much regardles of what the front is doing.

 

[bananu7]

Some more jumping today. The rear seems to handle landings quite alright. Actually the biggest "issue" with the bike right now is the fact that mud is getting everywhere, I need to add the fairings and replace the connectors with waterproof ones ASAP.

 

[bananu7]

I was very busy lately with the gas bike; as promised, I took it out and came back with a lot of mud but a decent result in the overall standings. No damage to me, minor damage to the bike (one plastic handbar shortened).



After coming back, I jumped on the CRF and had quite unexpected feelings:
1. Suspension feels much better than I remembered, and it seems in a very decent place now (I added quite a lot of preload in the rear recently, and run even less on the front, but still on stock spring rate).
2. I can close out the throttle with max power to the wheel without any issues even in sport. That part is less surprising considering I just got off a 40kW bike driven at full power for two days straight. I still have some headroom, so might experiment with settings a bit more.

I also got a chance to compare it to a heavily modded Surron with similar power and immediately found things that I did well on my build and things that I could improve on... I am getting really annoyed by the temporary measures around the battery mounting and wires, so those will likely be attacked first.

 

[bananu7]

I mounted the new loom and the display temporarily and was able to get readings from the controller. No errors reported, i tested it and it properly showed throttle error when I unplugged the cable. Seems reliable, but I took it off for now to fix a few software bugs and improve the cabling. I had a ride with a group today and didn't want to risk using a new loom.

Just before the ride I tried to swap the front tyre. This led me to scrapping the entire time/wheel:


The crack isn't just propagating from the repaired spot, it's on the other side of the rim as well. It could snap at any minute. I decided to play it safe, threw the old tyre out and borrowed the new wheel from the #2. Now I need either a new rim and set of spokes or a new wheel...

 

[bananu7]

I routed a new wire harness with new switches (and moved main enable to the right) and did some controller tuning:


throttle start voltage: 1.24V -> 1.0V
rate of rise: 120 -> 180
rate of decline: 70 -> 80
phase current: 9000 -> 9600
KI: 500 -> 550
mid flux weakening: 4000 -> 2000
soft start: 1 -> 8
reversing limit: 7% -> 15%
port settings: PB2 SW 1 -> 0 (sport mode now has physically latching button)

changes noticed:
- much slower start in L/M/H, feels like it takes a lot of time to build power (is slow start reversed? manual said higher is faster, but maybe it lied)
- S is good but couldn't test fully
- no motor jitter at the speed limit at L (couldn't test m and h but didn't notice any)
- reverse much stronger and goes a lot faster

i also connected my screen; it worked for a while, but then started showing "hardware overcurrent" error that didn't want to go away... i tried to reset it by pulling the main harness fuse which surprisingly threw a lot of sparks when connecting back in. The bike was running when in that "error" mode so i suspect it was a communication fluke; or maybe it does run with some errors? no idea. The display didn't get back on (and unfortunately i have no "comms missing" screen when it hangs waiting on can bus, i have to rectify that) and when measured i got 0V on my 5V line, so i suspect i fried the step-down module. Took everything home to inspect but now i gotta eat.

 

[j bjork]

Is soft start on the first page? From memory the quickest was 225 or something like that in rate of rise/decline. If you had engine braking on throttle release you might not want 225 on decline.. The other, maybe it was soft start 0 or 1. There was something for soft start on another page too, that you could just turn off.

 

[bananu7]

Is soft start on the first page? From memory the quickest was 225 or something like that in rate of rise/decline. If you had engine braking on throttle release you might not want 225 on decline.. The other, maybe it was soft start 0 or 1. There was something for soft start on another page too, that you could just turn off.

I'm not necessarily going for fastest reaction possible, I rode a few of my friends emotos and they were all too twitchy for me for enduro, hard to keep traction... Also sport mode is still very snappy. I was just kind of experimenting but maybe I should change one thing at a time... Pity I don't have a windows laptop and can only tune when i take the controller out, I need to figure something out.



In other news I completed my super cheap wheel, we'll see how it holds up.

 

[bananu7]

Tiny update: I ordered three sets of brake pads on Ali, one rear, two front, and I got three rear sets...
At least i got my money back no questions asked, so now i have a lot of spares to test that freaking rear brake. I also got a new pump for it, so incoming is a disassembly of the system; I need to measure the piston size of my existing pump first. If that comes out small, then I'll start suspecting the caliper and pads (and maybe the rear disk). I'll replace the caliper with the brand new one. I have another rear disk I bought for the CRF #2, so I can swap that in if needed. All in all, lots of hardware waiting for time to experiment, but I'll get it to work.

In other news, I've been thinking about how annoying it is to remove the power leads to access my harness every time. Right now, my setup is very simple: I have three M6 holed connectors (symmetrically on + and -) for battery, charging port and harness. They go in that order straight onto controller terminals (yes, charger is connected "to the controller", since the battery doesn't have a separate connector. That's a perk of a common port BMS). This works fine when assembled, but I keep thinking about "complicating" the setup a bit. What I'd like to do is to add an intermediate fuse box, and connect the charging port and the harness through that, with individual fuses. Right now those two extra cable sets have their individual fuses just hanging out, and that box could make it tidier. Also, that would allow me to move that box a bit outwards for easier manipulation - it's really hard to reach and connect the thick battery wires, and I really only need AWG7 for everything else.

That would also allow much easier splitting of aux 5V line for USB or aux 12V for lights and horn.

 

[bananu7]

I've replaced the front pads with the red EBCs, but that required me to drill out the pin holding them. Oh, the perks of working on a 20yo dritbike. I wanted to order a new OEM pin, but that costs more than a complete front caliper, pads included, from Aliexpress... In fact, I paid more for the good pads alone.

In the end I settled for a middle ground and ordered a couple of Aliexpress repair kits to do a rebuild:



They're actually better than OEM because you can replace both sliding pins, while Honda will only sell you one side. I polished the original ones in my brake but they are already severely corroded. I got another kit for #2 CRF because I suspect that one will be even worse.

I thought about machining the pin myself but I still don't have a rotary broach to make a hex head, and this kit seemed cheap enough and available.

I'm still struggling with the rear brake. I replaced the pump with a big ATV one, and it's definitely stiffer (which would indicate it actually has a larger piston). I can definitely squeeze it hard, it has a long lever, but the braking is still abysmal. After a couple tests, my rotor was hot, which indicates there is pressure in there, and now I'm suspecting the shitty pads. I'll replace them next and see how it goes.

 

[j bjork]

Did you want a bigger pump? That will mean you have to press harder to get strong braking. I think on both my bikes that the rear pump is a little bit too big, as it take harder press for hard rear braking.
It was really hard to bleed out all the air in the system though.

 

[bananu7]

Did you want a bigger pump? That will mean you have to press harder to get strong braking. I think on both my bikes that the rear pump is a little bit too big, as it take harder press for hard rear braking.
It was really hard to bleed out all the air in the system though.

Not really. I am just replacing components one by one to identify what's causing the braking issue. I bought that pump because it was cheap and readily available. Honestly other than the lever feel I can't say I feel much difference between them; I think it has a larger piston but much longer lever, which sort of cancels out. Maybe both have pistons that are too large, that's always an option too...

I think it's bled reasonably well, it just doesn't have enough power. I really hope the new pads will help.

 

[bananu7]

Replaced pads, didn't help at all. Now I'm almost certainly sure that I have a piston size mismatch. I've looked at E-XC and while it has a similarly-sized caliper, it actually has dual pistons... that's twice as much fluid flow...

To that effect:



i'm planning to machine a new, smaller piston and a sleeve. To get it twice as powerful, I'd need to reduce the diameter by 1/sqrt(2), so to about 7.78mm. I couldn't find any proper seals for that size, so I guess I'll try to get it to work with orings.

 

[j bjork]

Do you mean dual pistons like one on each side? In that case it doesn't matter, it is half the movement as the caliper is stationary. If it is dual pistons side by side, then you are correct.
Edit, I think I found that I should have a piston of something like 7.6mm to get the same power as in the front, so you are probably right

 

[bananu7]

I machined a new piston and a sleeve for it. Ended up boring the sleeve to 8.5mm to accept the 4x2mm o-rings over 5mm shaft.



The sleeve is a bit loose fit in the pump body, but it's a plastic prototype anyway. The main reason why i can't try it out right now is because I don't have a proper spring... The original one is too wide to fit in my new sleeve. I tried making a new one from some spare spring wire i had, but i need a much longer length of it to make a good job here, so the project will likely pause for a while until I can get some.

 

[SlowCo]

I hope you will replace the O-rings with proper seals like the original type. O-rings will not hold up at higher pressure/emergency braking.

I machined a new piston and a sleeve for it. Ended up boring the sleeve to 8.5mm to accept the 4x2mm o-rings over 5mm shaft.

 

[bananu7]

I hope you will replace the O-rings with proper seals like the original type. O-rings will not hold up at higher pressure/emergency braking.

It's not like the brake is "holding up" right now, it barely acts as a "slower down", not even mentioning emergency braking. I wanted to get hydraulic seals but they seem very hard to get in such a small size. I want to test if it works at all, but can't right now because of the spring.

 

[amberwolf]

Too bad it's a little bigger than a ballpoint pen spring. :lol:

Do you have any pneumatic tools? Some of the valves in the interconnects / etc might ahve a spring of a usable size (no guarantees).

Some pics from a page for parts for an air impact wrench https://www.aliexpress.us/item/3256805833604303.html found in a random google search to see what was inside

 

[bananu7]

Too bad it's a little bigger than a ballpoint pen spring. :lol:

Do you have any pneumatic tools? Some of the valves in the interconnects / etc might ahve a spring of a usable size (no guarantees).

Some pics from a page for parts for an air impact wrench https://www.aliexpress.us/item/3256805833604303.html found in a random google search to see what was inside

The original spring is in 1mm wire. I've ordered a couple of meters of 0.8mm and 1mm wire, and should be able to make my own then. I used some scrap wire i had but it was much too short to form ends comfortably and have the spring be of proper lenght. I found you need at least twice the amount of wire you need, to form both, tightly wound ends.

Either way i have a lot of other stuff to do in the meantime, so I'll just go back to it once I can make appropriate springs.

 

[j bjork]

What size is your cylinder if you can fit a sleeve with 8.5mm id inside?
Must be really big, like 12mm or something?
I think my cylinder is 9mm on the old bike, but I am not sure
The sale ad for it is gone, so I cant see what it said any longer.

 

[bananu7]

What size is your cylinder if you can fit a sleeve with 8.5mm id inside?
Must be really big, like 12mm or something?
I think my cylinder is 9mm on the old bike, but I am not sure
The sale ad for it is gone, so I cant see what it said any longer.

10.5. I think that's a nominal 10mm piston size with clearance for seals. That gives me wall thickness of 1mm. Seems fine even in plastic since it doesn't need to be strong at all, the casing takes all the pressure anyway.